There are weapons enthusiasts who enjoy firing automatic weapons. Automatic weapons not in private hands by a certain date are illegal to own. This has led to two phenomena. First, automatic weapons proven to be in private hands before the critical date are inordinately expensive. Second, many automatic weapons are modified to fire only in a semi-automatic mode for sale to individuals and non-governmental groups.
Because there is a demand for relatively inexpensive rapid fire weapons, there have been proposed and developed a variety of attachments for converting semi-automatic weapons into rapid fire weapons analogous to automatic fire. All of these attachments have their deficiencies. The most serious deficiency, particularly those devices incorporating multilobe cams to actuate the trigger, is that the cams are capable of being stopped at any position in the firing cycle, i.e. from a position where the weapon has just been discharged to a position where the weapon is just about to be discharged again. It can readily be seen that if the cam stops at a position where the weapon is just about to be fired, it is very dangerous because any slight movement of the weapon is capable of discharging a chambered round.
Of relevance to this invention are the disclosures in U.S. Pat. Nos. 4,276,808; 4,532,852 and 6,223,644.